A Crude Method to Test SWUV Transparency

A Crude method to test SWUV transparency
A helpful test for yellow-colourless-light coloured sapphires

Identification of sapphire usually does not pose any problems and can be easily accomplished by standard instruments. However the separation of natural from synthetic counterpart sometimes become challenging when light coloured clean sapphires (yellow to colourless) are encountered.

The separation between the natural and synthetic sapphires (especially light coloured - colourless/ yellow) is commonly done using magnification features. Presence of gas bubbles / unmelted powder along with ‘plato lines’ are observed in synthetics while inclusions like crystals, fluid inclusions, zoning features, parting planes, etc. in natural sapphires. However, often there are cases when these stones are free of inclusions and hence the separation becomes lot more challenging and time consuming

There is a need for a quick and effective method of separation of natural and synthetic yellow and colourless sapphires. One such method is SWUV transparency; this method has been known for quiet sometime, but not commonly used by student gemmologists and is considered to be a laboratory’s instrument

What is SWUV Transparency?

SWUV transparency is different from UV fluorescence; certain materials are transparent to some specific kinds of rays while opaque to some. For example, flesh / muscles are transparent to X-rays while the bones are opaque. But the same is not true with visible light/eye; both appear opaque. Also, diamonds are transparent to X-rays but Synthetic Cubic Zirconia is not; but both are transparent to visible light. Hence, it is not necessary that the materials, which are transparent to visible light, are also transparent to all various types of rays. The same principle goes with SWUV. Some materials may be transparent to SWUV (like flame-fusion colourless synthetic sapphires) and some materials are opaque (eg. natural sapphires or other synthetics).

This method has been documented by Yu R.M. and Healy D (1980) “A Phosphoroscope”, Journal of Gemmology, Vol 17, No. 4, p.250 and revisited by Elen. S & Fritsch. E. in “The Separation of Natural from Synthetic Colourless Sapphire”, Gems and Gemology, spring 1999, p 30- 41. These articles have presented an instrument “Phosphoroscope” to check SWUV transparency of gems, which uses a ‘phospor’ plate as the base for stones and as the UV rays fall on this plate, it fluoresce strong white.

Instead of building a complex instrument or purchasing it, presented here is a crude way of checking SWUV transparency using a standard gemmological UV lamp coupled with cheap daily use scraps!!

What is required?

A SWUV lamp (with proper viewing cabinet and accessories like protective glasses, gloves etc.)
An ordinary cosmetic mirror
A (broken) piece of fluorescent day light lamp (tube light) (Keep the white powdery material intact on the surface of the broken piece of lamp as it consists ‘phosphor’)

How to do the test?


Place the UV lamp in a dark room preferably with proper viewing cabinet (else rest it such a way that the UV light falls below).
Hold the piece of broken tube light such that the powdery side is at top. When switched on, the piece should glow due to the white powder.
Place the stones table down on this glass piece with powder surface.
Now place the mirror below such that one can view the reflection of the stones on the mirror.


Result:

Samples that do not allow the UV radiation to pass through and hit the powder will appear opaque (figure 5, right), while samples which allow the rays to pass through them will appear transparent with the darker perimeter on the mirror (figure 5, left). This difference depends on the amount of impurities present in the sample under test. Hence, a synthetic sapphire, which is a pure form of Al2O3 will appear transparent and a natural sapphire which consist of some impurities of Fe, Ti, or Ga will appear dark. Similarly, hydrothermal or flux stones containing higher percentage of impurities will appear dark and cannot be differentiated from natural counterparts by this method. In addition, if the flame fusion stones have undergone some sort of treatment the results become unusable. It is always advisable to compare any unknown material with the known natural or synthetic samples at the initial stages.


While checking for light yellow/colourless sapphires:
If a dark spot is observed: Natural or Synthetic (not very helpful)
If a bright spot is observed: Synthetic (conclusion)

The point to remember is when a bright spot is observed, the sapphire is confirmed synthetic but when a dark spot is observed it may be natural or synthetic. Such a method of checking SWUV Transparency is very easy to construct, cheap and highly effective when used properly. However certain precautions are to be taken as follows:
Take precautions not to expose unprotected skin or eye to SWUV radiations. Use protective eyewear and gloves.
The broken piece of tube light may be sharp and dangerous. Be very careful and students are specifically advised to use, store and dispose off the pieces carefully.
Highly included and opaque stones may provide wrong results.
Always start with the known set of stones and compare the results with unknown samples. Do not skip the routine gemmological tests.

This method if applied properly and with care will prove to be a fast and effective method of confirming light coloured synthetic sapphires. If you have any problem in understanding the process or the principle, feel free to contact me or the Gem Testing Laboratory, Jaipur.

PS This article was submitted for the Lab Information Circular March 2008. To get the complete issue inform me or contact GTL, Jaipur. I acknowledge Gagan Sir, Khan Sir and Meenu Mam, GTL for their co-operation and support

Leaving Gem Testing Laboratory, Jaipur - 25th dec 07

Hello friends and well wishers..There is something I wanted to convey...

Coming 25th of Dec is going to be my last day that I shall be officially be a part of the Gem Testing Laboratory, Jaipur. I have already submitted my resignation letter and make another beginning with the new year.

I have been associated with GTL, Jaipur for three years now (1 year as a student and 2 years of my job here). It has been a very tricky decision and am still like...I am still in mixed emotions. GTL has played an important part in bringing me international fame and has become very much a part of my identity.

For my well wishers...regarding my future...this is what I have planned...

A months break in Chennai during which I shall try to visit and work on gemstone deposits in South India and Orissa particularly. After which I shall spend three months in Bangkok to extensively understand the market, trends, treatments and all that I can study about gemstones and jewellery. This I believe would play an important part in shaping my career and understanding the subject much better practically. "From the current options I have, the one I have taken is the best so far...However, I have always kept all my options open and decisions can be changed even now" (in case I find something more interesting)

Though Christmas would be my last day at GTL, my affair with it shall continue for all the years to come by. 24th would be the last working day at GTL and I shall represent GTL for the last time on the 25th of Dec at the Jaipur Jewellery Show 2007.

Right now this is all that I can say....however, I shall soon come up with another blog posting detailing my gemological career so far....from how I got into this field inspite of my father being in a completely different business...to what I have achieved so far. Look forward to my journey as a gemologist so far. I have tried my best not to be emotional here....still there remains a lot unexpressed.


I am in Jaipur till the 28th of Dec 2007 before leaving to Chennai via Bhandakji.

P.S. Due to some reasons, all the contacts stored in my communicator has been deleted....that was my only source of all mobile and phone numbers for me. All readers this is applicable to...please email me your contact details on chaman_golecha@yahoo.com or send a scrap (or message for privacy) in Orkut.

Regards
Chaman Golecha

"Bhooton ka Bhangarh" Adventure to the most haunted place in India...!!!

Since a very young age, I have been a lot into traveling. This year (2007) alone I have already made it to Hong Kong, Bangkok, many places in Europe including London, Switzerland, France, Belgium, Holland, Germany etc., In India-Chennai, Bhandakji, Nainital-Bhimtal, Agra, Delhi etc. All of this either with my family or friends.

It was the first time that we were planning a trip with my colleagues. After a long question answer, I was able to convince them to a positive. Yes they were ready...!!

"But where ?"

"You suggest"

"You have planned an outing...any place worth visiting that we return back on the same day?"

"Bhangarh" I said

There were some moments of silence. A half of them had not heard of the place and seemed to be thinking if they had heard of it. And those who had heard of it were just silent. They knew what I was speaking of.


"Bhangarh, bhooton wala??" Goplaji said hesitantly



Then started a series of discussions and arguments whether or not it was worth visiting the place. We googled up the place and now everybody was keen to visit the place. All with just a single question in mind...kya hame bhooth dikhega

This is what the wikipedia said about Bhangarh.

"The local folks say that due to a curse the whole town was vacated overnight. According to the story of the curse, if the town was ever rediscovered the township would not be found, but only temples would show up.

True to the story, only temples dot the landscape and even far up on the mountains only shrines can be seen. It is said that nobody returns from there who stays after dark.


By the Government of India rules there has to be an office of Archaeological Survey of India (ASI) beside every historical structure in India. But even government authorities did not dare to open an office there. They opened their office about one kilometer away from the ruins of Bhangarh. Even this office is close to a temple because of this myth. ASI has put a signboard at Bhangarh saying, "Staying after sunset is strictly prohibited in this area."'Bold text'"



The excitement kept growing as we kept discovering more and more about the place. For a week, anyone I met, this question was certain in all those conversations "Have you heard of Bhangarh". Net, shopkeepers, workers, relatives, friends noone was spared. I had heard of the place first from Ankur and Vikas, two of my very close friends in Jaipur. Since then I always wanted to see it. This came as one opportunity.

Sunday 16th Dec 07 was the day. Six in all we hired a qualis and started morning at 8:20 and first halt was 20 mins later for breakfast. Samosa, Kachori, Mirchi Bajji, Jalebi and all such stuff - some of my favorites. Then started a 2 hour drive to the place. It is near Alwar and falls near Dausa.

The first view of Bhangarh itself was much to its name. From a distance, we could make out mountains with some ruined palace like built up. The last three kilometers were among the worst roads, and finally we were there. It was all fenced with mountains on three sides and a wall built in the front with a gate which could open only partially just enough to allow a single person in at a time.



Outside the gate, an old lady was begging true to the Indian image on this. The first thing one saw on entering the ruined village was a temple of Hanuman. A pandit stood there.

"Bhangarh dekhna hai?"

"Haan"

"Chalo koi chinta mat karo...aap log pehle ghum aao phir main aapko saari kahani sunata hoon"

"Kahan ghume?" I asked

"Is gaavn mein koi rehta nahi hai, tho bas aap mandir, wahan mahal aur bazaar dekhlo. Yahan ki saari kahani woh upar jo dikh raha hai naa...ussi se sab kuch lena hai"

He pointed to a small dome built on top of the mountain which had all to do with why Bhangarh is now a deserted village and also haunted.

As we were about to start, another person was going inside. He was ready to be out guide (off-course not by profession but was a good Samaritan.) We saw some temples which now had many cracks, the ruins of what looked like a market of the yesteryears. It was Bhangarh where the shooting of a famous hindi movie Karan Arjun took place starring Salman Khan and Shah Rukh Khan (involves re-incarnation). Bhangarh was beautiful and makes one think...<span style="font-weight:bold;">Why did the village become vacated overnight??. There was a small water body with some water snakes and fish in it. Temples with some idols missing and a palace.

The palace was amazing. Though ruined, we could feel how beautiful it would have been during the green times. Built on a mountain, the palace had three floors above and four floors dug in underground. The only entrance below were some square shaped gaps which was just enough to allow a person at a time to enter. The small entrance was probably made so that the king, queen and some important people were safe even if attacked suddenly. We did not go in as it was quiet dark inside (and no one wanted to go in otherwise also...what if we were struck inside??? ha).




We felt no ghost or bhooth but rather found the place very interesting. A complete village and looked as if everyday it would be hustling and bustling with trade and people all around. But now, we could scarcely find people in that 6 km x 4 km village. We were also shown a tree from the roots of which water seemed to flow and off-course a crab in it and some kevedon ke ped.

Another attraction was the randiyon ka mahal (palace of the prostitutes). A very open built up, it added nice colour to the already interesting village of Bhangarh. I jokingly commented...

"Yeh abhi working nahi hai !!"







After spending some time around, we finally returned to the pandit to listen to the story of Bhangarh. Here is what it was in short...

" Bhangarh was the capital of the empire in Rajasthan around 565 years ago and was quiet popular at that time. It was named after its king Bhanu Pratap Singh. There also lived a tantrik (a person who performs various degrees of magic) who had always desired for the queen. The queen was very beautiful and faithful to the king...so the tantrik decided to use magic so that the queen come to him.

As the maid of the queen went to purchase oil, the tantrik applied some magic on it such that as soon as the queen touches the oil, she would come running to her. The queen however was very clever and came to know that something was fishy. To test, she poured some of it on a huge stone. The stone flew to tantrik and hit him on his chest. Just before dying, the Tantrik cursed that the village be emptied overnight else nobody would survive.

Most of the people fled the village, including the king and the queen (who later reached Amer then Jaipur became the capital of the empire as it is now). Those who were "brave" and wanted to see what would happen, died. Their souls which has not yet rested seems to haunt around. "





All of us were listening without a word as the pandit continued...

"abhi koi bhoot pret nahi hai"



Though i still do not believe in the story, he claimed it to be true as it has been told generations to generations. Figure:This leads to four floors below...dare to get in??? True or false, it was a fascinating experience to see the village.





It makes one think...why did the village empty overnight...if the story of Tantrik is false, what is the truth then...this answer still haunts me. (maybe some flood, or some other calamaties?)

Overall it was a wonderful experience. On our way back, we just had a look at Ajabgarh from the car itself and then headed to a dhaba to have dinner. After that we reached Jaipur at around 5pm. A fantastic trip had come to end but the question still remains....kya wahan bhoot aaj bhi raat ko aate hain??


Just a last view on Bhangarh which i think is most probably the answer...

Figure: The famous palace of the prostitutes...or randiyon ka mahal...!!!

Myth: No one is allowed inside after 4pm and is gaurded by police as ghosts wake up in the night. No one has ever come out alive after going in during the night.

Fact: There are high chances of some treasures being found there as the place was vacated overnight (due to unknown reasons). Probably the government encourages the story of Tantrik and ghosts so that it keeps away people who come in search of some treasures. Risky but money can drive anyone to do this.

Hope you enjoyed the blog...post your comments....!!!!

Nailhead spicule in yet another Natural emerald

by Chaman Golecha

"A STUDY OF NAIL-HEAD SPICULE INCLUSIONS IN NATURAL GEMSTONES" was our first mark in the index as a main article (earlier reports were in the short GNI section) of the Gems and Gemology (A quarterly of the Gemological Institute of America, USA). The article published is published in the current issue of the magazine (Vol.43, No.3, Fall 2007). One may read the abstract here.

Within few days of receiving the magazine, we encountered another Natural emerald with prominent true Nail Head spicules. Since, the article was already published and reporting this would be of no use, I decided to kick start my blog with this. What follows is a report on that emerald.

Figure: Nail Head spicule in Synthetic emerald, courtesy of GIA website.

We encountered this stone just 3 days back (10th Dec 07). The specimen weighing 3.71 cts, oval mixed cut was submitted for testing at the Gem Testing Laboratory, Jaipur, India. Initial analysis using standard gemmological techniques revealed properties (Refractive Index, Specific Gravity, Spectrum, Polariscope, Dichroscope reactions etc.) typical of emerald, Natural or Synthetic. Magnification is the most important feature in the separation of Natural and synthetic gemstones. This specimen was no exception.

Upon magnification, several parallel zones were observed with some elongated inclusions oriented perpendicular to the zones. Examination of these elongated feaures revealed NHS inclusions. This emerald had much clearer and well developed spicules than the one we had reported in the G&G.

Figure: Parallel zones and Nail head spicule inclusions. .

Some of the spicules had a very long cone along with clear phase. The base of the inclusions was made of cluster of crystal inclusions which somewhat appeared like flakes of some brown mineral. Due to lack of Raman, we could not determine the nature of the inclusions. All the inclusions were oriented along the optic axes which was determined by observation along crossed polars.

Though almost all the spicules had their cones pointing towards the same direction, a few of them were oriented at 180 degrees i.e. exactly opposite direction (still along the optic axes).

View along girdle revealed undulating features "chevron" effect as in the figure. Both the Nail head spicules and "chevron" growth features have traditionally been associated with hydrothermal synthetic stones. However this specimen proved to be an exception. The natural identity of this stone was made by the presence of zoning features, liquid films, crystal inclusions (mica?) etc. Further confirmation was obtained by FTIR which revealed features of Natural emerald.

Figure: Undulating pattern somewhat resembling chevron growth patterns.

Time and again, I have encountered features which have traditionally associated with Natural in Synthetic and vice-versa. Such specimens, time and again reminds one of careful and complete examination. Also one should never rely on a single feature to make an identification and such a stone could easily mislead a novice gemmologist.

P.S.: Click on the images to magnify them for a clearer view. Comments are welcome...!!

Acknowledgment: Mr. Gagan Choudhary and Mr. Mustaqueem Khan for all the co-operations and helpful discussions.

PHOTOMICROGRAPHS OF OTHER INCLUSIONS IN THE ABOVE SPECIMEN

More Nail head spicule inclusions:



Sheen observed along parallel zones: